Optical device, light-source device, detector, and electronic device

ABSTRACT

An optical device and a light-source device. The optical device includes a first substrate having a first plane and elements, and a second substrate having a second face that faces the first plane. The elements are disposed on the first substrate to emit or receive light in a direction intersecting with the first plane. The second substrate includes lenses disposed to correspond to the elements, and the second substrate extends in a first direction parallel to the second face to contact the first plane. The second substrate has a joint used to determine spacing between the first substrate and the second substrate, and the joint contacts the first substrate with an area smaller than a maximum size of cross-sectional area parallel to the second face of the joint. The light-source device includes the optical device and a driver to drive the optical device.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is based on and claims priority pursuant to 35U.S.C. §119(a) to Japanese Patent Application No. 2019-114074, filed onJun. 19, 2019, in the Japan Patent Office, the entire disclosure ofwhich is hereby incorporated by reference herein.

BACKGROUND Technical Field

Embodiments of the present disclosure relate to an optical device, alight-source device, a detector, and an electronic device.

Background Art

In the known processes of manufacturing an on-vehicle ignition systemincluding a vertical cavity-surface emitting laser (VCSEL) device, atleast a pair of substrates are bonded and fixed together in a directmanner using adhesive such as an ultraviolet (UV)-curable resin and therelative positions of these substrates are adjusted.

SUMMARY

Embodiments of the present disclosure described herein provide anoptical device and a light-source device. The optical device includes afirst substrate having a first plane and a plurality of elements, theelements being disposed on the first substrate to emit or receive lightin a direction intersecting with the first plane, and a second substratehaving a second face that faces the first plane. The second substrate isprovided with a plurality of lenses disposed to correspond to theelements, and the second substrate extends in a first direction parallelto the second face to contact the first plane. The second substrate hasa joint used to determine spacing between the first substrate and thesecond substrate, and the joint contacts the first substrate with anarea smaller than a maximum size of cross-sectional area parallel to thesecond face of the joint. The light-source device includes the opticaldevice and a driver configured to drive the optical device, and each oneof the elements is an element to emit light.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of embodiments and the many attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings.

FIG. 1A is a top view of an optical device according to a control sampleof embodiments of the present disclosure.

FIG. 1B is a sectional view of an optical device according to a controlsample of embodiments of the present disclosure.

FIG. 2 is a sectional view indicative of how adhesive behaves when aspacer according to a first example is adopted.

FIG. 3 is a sectional view indicative of how adhesive behaves when aspacer according to a second example is adopted.

FIG. 4 is a sectional view indicative of how adhesive behaves when aspacer according to a third example is adopted.

FIG. 5 is a sectional view indicative of how adhesive behaves when aspacer according to a fourth example is adopted.

FIG. 6 is a sectional view indicative of how adhesive behaves when aspacer according to a first example is adopted and a MLA substrate isbonded onto a VCSEL array substrate with inclination.

FIG. 7 is a partially magnified view of the sectional view of FIG. 6.

FIG. 8 is a sectional view indicative of how adhesive behaves when aspacer according to a second example is adopted and a MLA substrate isbonded onto a VCSEL array substrate with inclination.

FIG. 9 is a partially magnified view of the sectional view of FIG. 8.

FIG. 10 is a sectional view indicative of how adhesive behaves when aspacer according to a third example is adopted and a MLA substrate isbonded onto a VCSEL array substrate with inclination.

FIG. 11 is a partially magnified view of the sectional view of FIG. 10.

FIG. 12 is a sectional view indicative of how adhesive behaves when aspacer according to a fourth example is adopted and a MLA substrate isbonded onto a VCSEL array substrate with inclination.

FIG. 13 is a partially magnified view of the sectional view of FIG. 12.

FIG. 14A is a perspective view of a model.

FIG. 14B is a sectional view of a model.

FIG. 15A is a perspective view indicative of a squeezed-out excess ofadhesive of high viscosity when a spacer according to a first example isadopted.

FIG. 15B is a sectional view indicative of a squeezed-out excess ofadhesive of high viscosity when a spacer according to a first example isadopted.

FIG. 16A is a perspective view indicative of a squeezed-out excess ofadhesive of high viscosity when a spacer according to a second exampleis adopted.

FIG. 16B is a sectional view indicative of a squeezed-out excess ofadhesive of high viscosity when a spacer according to a second exampleis adopted.

FIG. 17A is a perspective view indicative of a squeezed-out excess ofadhesive of high viscosity when a spacer according to a third example isadopted.

FIG. 17B is a sectional view indicative of a squeezed-out excess ofadhesive of high viscosity when a spacer according to a third example isadopted.

FIG. 18A is a perspective view indicative of a squeezed-out excess ofadhesive of low viscosity when a spacer according to a first example isadopted.

FIG. 18B is a sectional view indicative of a squeezed-out excess ofadhesive of low viscosity when a spacer according to a first example isadopted.

FIG. 19A is a perspective view indicative of a squeezed-out excess ofadhesive of low viscosity when a spacer according to a second example isadopted.

FIG. 19B is a sectional view indicative of a squeezed-out excess ofadhesive of low viscosity when a spacer according to a second example isadopted.

FIG. 20A is a perspective view indicative of a squeezed-out excess ofadhesive of low viscosity when a spacer according to a third example isadopted.

FIG. 20B is a sectional view indicative of a squeezed-out excess ofadhesive of low viscosity when a spacer according to a third example isadopted.

FIG. 21A is a top view of an optical device according to a firstembodiment of the present disclosure.

FIG. 21B is a sectional view of an optical device according to the firstembodiment of the present disclosure.

FIG. 21C is a partially magnified view of the sectional view of FIG.21B.

FIG. 22A is a bottom view of an MLA substrate according to the firstembodiment of the present disclosure.

FIG. 22B is a sectional view of an MLA substrate according to the firstembodiment of the present disclosure.

FIG. 23 is a sectional view of a VCSEL array substrate according to thefirst embodiment of the present disclosure.

FIG. 24 is a flowchart of the processes of a method of manufacturing anoptical device, according to the first embodiment of the presentdisclosure.

FIG. 25A is a top view of adhesive according to the first embodiment ofthe present disclosure.

FIG. 25B is a sectional view of adhesive according to the firstembodiment of the present disclosure.

FIG. 26A is a top view of an optical device according to a modificationof the first embodiment of the present disclosure.

FIG. 26B is a sectional view of an optical device according to amodification of the first embodiment of the present disclosure.

FIG. 27A is a bottom view of an MLA substrate according to amodification of the first embodiment of the present disclosure.

FIG. 27B is a sectional view of an MLA substrate according to amodification of the first embodiment of the present disclosure.

FIG. 28A is a plan view of an optical device according to a secondembodiment of the present disclosure.

FIG. 28B is a sectional view of an optical device according to thesecond embodiment of the present disclosure.

FIG. 29A is a bottom view of an MLA substrate according to the secondembodiment of the present disclosure.

FIG. 29B is a sectional view of an MLA substrate according to the secondembodiment of the present disclosure.

FIG. 30 is a flowchart of the processes of a method of manufacturing anoptical device, according to the second embodiment of the presentdisclosure.

FIG. 31 is a bottom view of an MLA substrate of large format, accordingto the second embodiment of the present disclosure.

FIG. 32A is a top view of adhesive according to the second embodiment ofthe present disclosure.

FIG. 32B is a sectional view of adhesive according to the secondembodiment of the present disclosure.

FIG. 33A is a first sectional view illustrating a method ofmanufacturing an optical device, according to the second embodiment ofthe present disclosure.

FIG. 33B is a second sectional view illustrating a method ofmanufacturing an optical device, according to the second embodiment ofthe present disclosure.

FIG. 33C is a third sectional view illustrating a method ofmanufacturing an optical device, according to the second embodiment ofthe present disclosure.

FIG. 34 is a sectional view illustrating chipping according to thesecond embodiment of the present disclosure chipping.

FIG. 35 is a sectional view of an optical device according to a thirdembodiment of the present disclosure.

FIG. 36A is a bottom view of a part of a large-format MLA substrate usedin the third embodiment of the present disclosure.

FIG. 36B is a sectional view of a part of a large-format MLA substrateused in the third embodiment of the present disclosure.

FIG. 37A is a first sectional view illustrating a method ofmanufacturing an optical device, according to the third embodiment ofthe present disclosure.

FIG. 37B is a second sectional view illustrating a method ofmanufacturing an optical device, according to the third embodiment ofthe present disclosure.

FIG. 37C is a third sectional view illustrating a method ofmanufacturing an optical device, according to the third embodiment ofthe present disclosure.

FIG. 38A is a first sectional view illustrating a method ofmanufacturing an disclosure.

FIG. 38B is a second sectional view illustrating a method ofmanufacturing an optical device, according to a modification of thethird embodiment of the present disclosure.

FIG. 38C is a third sectional view illustrating a method ofmanufacturing an optical device, according to a modification of thethird embodiment of the present disclosure.

FIG. 39A is a bottom view of an MLA substrate according to a fourthembodiment of the present disclosure.

FIG. 39B is a sectional view of an MLA substrate according to the fourthembodiment of the present disclosure.

FIG. 40A is a bottom view of an MLA substrate according to a firstmodification of the fourth embodiment of the present disclosure.

FIG. 40B is a sectional view of an MLA substrate according to the firstmodification of the fourth embodiment of the present disclosure.

FIG. 41A is a bottom view of an MLA substrate according to a secondmodification of the fourth embodiment of the present disclosure.

FIG. 41B is a sectional view of an MLA substrate according to the secondmodification of the fourth embodiment of the present disclosure.

FIG. 42 is a diagram illustrating a schematic configuration of adistance-measuring apparatus as an example of detector.

FIG. 43 is a diagram illustrating a configuration of adistance-measuring apparatus according to a sixth embodiment of thepresent disclosure.

The accompanying drawings are intended to depict embodiments of thepresent disclosure and should not be interpreted to limit the scopethereof. The accompanying drawings are not to be considered as drawn toscale unless explicitly noted.

DETAILED DESCRIPTION

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentdisclosure. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“includes” and/or “including”, when used in this specification, specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

In describing example embodiments shown in the drawings, specificterminology is employed for the sake of clarity. However, the presentdisclosure is not intended to be limited to the specific terminology soselected and it is to be understood that each specific element includesall technical equivalents that have the same structure, operate in asimilar manner, and achieve a similar result.

Embodiments of the present disclosure are described below in detail withreference to the accompanying drawings. Note that in the description andthe drawings of the embodiments of the present disclosure, likereference signs are given to elements with substantially the samefunctional configuration. Accordingly, overlapping descriptions areomitted where appropriate. In the following description of the presentdisclosure, it is assumed that the direction in which an optical deviceemits light is the Z-axis direction, and that the two directionsorthogonal to each other on a plane perpendicular to the Z-axisdirection using a right-hand system are the X-axis direction and theY-axis direction. Moreover, it is assumed that the +Z-axis direction ison the upper side. However, no limitation is indicated thereby, and suchan optical device or the like may be used under upside-down conditions,or may be arranged at any desired angle.

Firstly, the gist of the present disclosure is described below withreference to control samples.

The role of each microlens is to control the angle of radiation of thelaser beam that is emitted from a vertical cavity-surface emitting laser(VCSEL) device. In order to achieve such functions, the relativepositions of the VCSEL device and the microlenses need to be adjusted tominimize the positional displacement between the center of thelight-emitting point of the VCSEL device and the center of eachmicrolens. Moreover, as a matter of course, the distance between thelight-emitting point of the VCSEL device and each lens needs to bematched with a design value. For example, when the distance between aVCSEL array substrate on which a plurality of VCSEL devices are arrayedand a microlens array (MLA) substrate on which a plurality ofmicrolenses are arrayed takes a value greater than a design value, thereare some cases in which a laser beam that is emitted from a differentVCSEL device is incident on a microlens that is arranged for aparticular corresponding VCSEL device and stray light emerges. On thecontrary, when the distance between the VCSEL array substrate and theMLA substrate takes a value smaller than a design value, there are somecases in which the angle of radiation of the laser beam that has passeda microlens becomes wider than necessary. When the distance between theVCSEL array substrate and the MLA substrate is uneven, the angle ofradiation tends to differ for every VCSEL device. In particular, whenthe VCSEL array substrate and the MLA substrate are bonded together in astate of wafer, the control of distance tends to be difficult.

In order to handle such a situation, an MLA substrate may be providedwith some spacers each of which has even height and the VCSEL arraysubstrate and the MLA substrate may be bonded together through thosespacers.

FIG. 1A is a top view of an optical device 9 according to a controlsample of embodiments of the present disclosure.

FIG. 1B is a sectional view of the optical device 9 according to thepresent control sample of embodiments of the present disclosure.

More specifically, FIG. 1B is a diagram illustrating a cross-sectionalview along line I-I of FIG. 1A.

The optical device 9 according to the control sample as illustrated inFIG. 1A and FIG. 1B includes a microlens array (MLA) substrate 901provided with a base 901 c, a plurality of microlenses 901 a, and a pairof spacers 901 b. Each of the spacers 901 b is shaped like a rectangularparallelepiped that extends in the Y-axis direction. The pair of spacers901 b are arranged on both sides of the MLA that is composed of themicrolenses 901 a in the X-axis directions. A VCSEL array substrate 910is arranged on a submount substrate 911. The VCSEL array substrate 910includes a plurality of VCSEL devices 910 a. Moreover, a bottom face 901d of each of the spacers 901 b contacts a top face 910 b of the VCSELarray substrate 910. The pair of spacers 901 b are fixed to the VCSELarray substrate 910 by adhesive 920.

With the optical device 9 according to the present control sample, thedistance between the VCSEL array substrate 910 and the MLA substrate 901can be stabilized due to the spacers 90 lb. However, when the VCSELarray substrate 910 and the MLA substrate 901 are bonded together, thespacers 901 b squeeze the adhesive 920, and the shape of thesqueezed-out adhesive 920 may be distorted. When the MLA substrate 901is bonded onto the VCSEL array substrate 910 with inclination, theadhesive 920 sticks out to one side in a greater amount than to theother side of the joint, and the amount of the spread of the adhesive920 is unbalanced. In order to achieve downsizing, it is desired thatthe distance between the light-emitting area and the bonding area benarrow. However, when the adhesive 920 that is squeezed out from thespacers 901 b is spread out to the light-emitting unit of the VCSELdevice 910 a or the lens unit of the MLA substrate 901, the opticalproperties deteriorate. For example, as illustrated in FIG. 1B, theadhesive 920 may partly block the route of the laser beams L that areemitted from the VCSEL device 910 a. In such cases, the laser beams Lmay be reflected or absorbed by the adhesive 920.

For this reason, the shape of the adhesive that is used to fix spacersonto a VCSEL array substrate needs to be stabilized. In the embodimentsof the present disclosure, the spacers are configured to have a specificshape. As a result, the relative positions of the VCSEL array substrateand the MLA substrate is precisely determined in a favorable and stablemanner, and the shape of the adhesive is stabilized.

The shape of the spacers is described below.

FIG. 2 is a sectional view indicative of how the adhesive 920 behaveswhen the spacer 951 according to the first example is adopted.

FIG. 3 is a sectional view indicative of how the adhesive 920 behaveswhen the spacer 952 according to the second example is adopted.

FIG. 4 is a sectional view indicative of how the adhesive 920 behaveswhen the spacer 953 according to the third example is adopted.

FIG. 5 is a sectional view indicative of how the adhesive 920 behaveswhen the spacer 954 according to the fourth example is adopted.

As illustrated in FIG. 2, a spacer 951 according to the first examplehas a rectangular shape in cross section. When the spacer 951 is adoptedand the spacer 951 is pressed against the VCSEL array substrate 910, abottom face 951 a of the spacer 951 contacts the adhesive 920, and thenthe adhesive 920 sticks out to the surrounding area of the spacer 951.When the bottom face 951 a of the spacer 951 contacts the top face 910 bof the VCSEL array substrate 910, the adhesive 920 is squeezed out toboth sides of the spacer 951, and the adhesive 920 does not remainbetween the spacer 951 and the VCSEL array substrate 910.

As illustrated in FIG. 3, the bottom end of the rectangular shape of thespacer 952 according to the second example is chamfered, and the spacer952 has a shape in cross section where an oblique face 952 b that isconnected to a bottom face 952 a is formed. When the spacer 952 isadopted and the spacer 952 is pressed against the VCSEL array substrate910, an bottom face 952 a of the spacer 952 contacts the adhesive 920,and then the adhesive 920 sticks out to the surrounding area of thespacer 952 along an oblique face 952 b. When the bottom face 952 a ofthe spacer 952 contacts the top face 910 b of the VCSEL array substrate910, some of the adhesive 920 is squeezed out to both sides of thespacer 952, and the rest of the adhesive 920 remains between the spacer952 and the VCSEL array substrate 910.

As illustrated in FIG. 4, the spacer 953 according to the third examplehas a shape in cross section where an curved face 953 a is formed, atthe bottom end of the rectangular shape. When the spacer 953 is adoptedand the spacer 953 is pressed against the VCSEL array substrate 910, afront end of a curved face 953 a of the spacer 953 contacts the adhesive920, and then the adhesive 920 sticks out to the surrounding area of thespacer 953 along the curved face 953 a. When the front end of the curvedface 953 a of the spacer 953 contacts the top face 910 b of the VCSELarray substrate 910, some of the adhesive 920 is squeezed out to bothsides of the spacer 953, and the rest of the adhesive 920 remainsbetween the spacer 953 and the VCSEL array substrate 910.

As illustrated in FIG. 5, the spacer 954 according to the fourth examplehas a shape in cross section where a step is formed at the bottom end ofthe rectangular shape and a side face 954 b that is connected to abottom face 954 a is formed. When the spacer 954 is adopted and thespacer 954 is pressed against the VCSEL array substrate 910, a bottomface 954 a of the spacer 954 contacts the adhesive 920, and then theadhesive 920 sticks out to the surrounding area of the spacer 954 alonga side face 954 b. When the bottom face 954 a of the spacer 954 contactsthe top face 910 b of the VCSEL array substrate 910, some of theadhesive 920 is squeezed out to both sides of the spacer 954, and therest of the adhesive 920 remains between the spacer 954 and the VCSELarray substrate 910.

Assuming that the shapes of the spacers 951 to 954 are same except thebottom ends and the materials for and the amount of the adopted adhesive920 are the same, the distance X from the spacer 951 to the end of theadhesive 920, which is squeezed out to an external area, becomes thelongest in a planar view when the spacer 951 is adopted. In other words,the amount of the squeezed-out excess of the adhesive 920 can becontrolled when one of the spacers 952 to 954 are adopted than when thespacer 951 is adopted. When the sizes of the spacers 951 to 954 aregreater in the Y-axis direction, the amount of squeezed-out excess ofthe adhesive 920 tends to vary more easily. When one of the spacers 952to 954 is adopted, the speed with which the adhesive 920 spreads can bereduced to prevent the amount of the squeezed-out excess from varying.

As will be described later, there are some cases in which the MLAsubstrate 901 is inclined with reference to the VCSEL array substrate910 when their bonding processes start. In order to deal with such asituation, imbalanced spread of the adhesive 920 can be prevented byadopting one of the spacers 952 to 954.

FIG. 6 is a sectional view indicative of how the adhesive 920 behaveswhen the spacer 951 according to the first example is adopted and theMLA substrate 901 is bonded onto the VCSEL array substrate 910 withinclination.

FIG. 7 is a partially magnified view of the sectional view of FIG. 6.

FIG. 8 is a sectional view indicative of how the adhesive 920 behaveswhen the spacer 952 according to the second example is adopted and theMLA substrate 901 is bonded onto the VCSEL array substrate 910 withinclination.

FIG. 9 is a partially magnified view of the sectional view of FIG. 8.

FIG. 10 is a sectional view indicative of how the adhesive 920 behaveswhen the spacer 953 according to the third example is adopted and theMLA substrate 901 is bonded onto the VCSEL array substrate 910 withinclination.

FIG. 11 is a partially magnified view of the sectional view of FIG. 10.

FIG. 12 is a sectional view indicative of how the adhesive 920 behaveswhen the spacer 954 according to the fourth example is adopted and theMLA substrate 901 is bonded onto the VCSEL array substrate 910 withinclination.

FIG. 13 is a partially magnified view of the sectional view of FIG. 12.

As illustrated in FIG. 6 and FIG. 7, when the spacer 951 is adopted andthe MLA substrate 901 is bonded onto the VCSEL array substrate 910 withinclination, a front end of the spacer 951 contacts the adhesive 920 ata position significantly deviating from the center of the adhesive 920,and the adhesive 920 sticks out. For this reason, the adhesive 920sticks out to one side in a greater amount than to the other side.

By contrast, when the spacer 952 is adopted and the MLA substrate 901 isbonded onto the VCSEL array substrate 910 with inclination, asillustrated in FIG. 8 and FIG. 9, a front end of the spacer 952 contactsthe adhesive 920 approximately at the center. Accordingly, imbalancedspread of the adhesive 920 can be prevented. As illustrated in FIG. 10and FIG. 11, the same thing can be said for cases in which the spacer953 is adopted. As illustrated in FIG. 12 and FIG. 13, the same thingcan be said for cases in which the spacer 954 is adopted.

Some example cases in which the amount of squeezed-out excess of theadhesive 962 when the spacers 951 to 953 are adopted are describedbelow. In such example cases described below, it is assumed that twodifferent kinds of adhesive with varying viscosity are used.

FIG. 14A is a perspective view of a model.

FIG. 14B is a sectional view of a model.

FIG. 14B is a sectional view indicated by a broken line II of FIG. 14A.In this model, the adhesive 962 is arranged on a planar adherend 961 ina straight line. The length, the width, and the height of the adhesive962 are 550 micrometers (μm), 50 μm, and 10 μm, respectively.

Firstly, the amount of squeezed-out excess when the viscosity of theadhesive 962 is high is described.

FIG. 15A is a perspective view indicative of a squeezed-out excess ofthe adhesive 962 of high viscosity when the spacer 951 is adopted.

FIG. 15B is a sectional view indicative of a squeezed-out excess of theadhesive 962 of high viscosity when the spacer 951 is adopted.

FIG. 15B is a sectional view indicated by a broken line II of FIG. 15A.In the present example, the length and width of the spacer 951 is 500 μmand 30 μm, respectively. When the spacer 951 is adopted, the adhesive962 spreads in a convex shape in the range of 62.4 μm having the spacer951 in the center. In other words, the adhesive 962 is squeezed out toboth sides by 16.2 μm each. The radius of curvature of the adhesive 962becomes 16.2 μm, and the maximum height of the adhesive 962 is 16.2 μm.

FIG. 16A is a perspective view indicative of a squeezed-out excess ofthe adhesive 962 of high viscosity when the spacer 952 is adopted.

FIG. 16B is a sectional view indicative of a squeezed-out excess of theadhesive 962 of high viscosity when the spacer 952 is adopted.

FIG. 16B is a sectional view indicated by a broken line II of FIG. 16A.In the present example, the length and width of the spacer 952 is 500 μmand 30 μm, respectively. The bottom end of the spacer 952 is chamferedby 10 μm at the angle of 45 degrees. When the spacer 952 is adopted, theadhesive 962 spreads in a convex shape in the range of 58.6 μm havingthe spacer 952 in the center. In other words, the adhesive 962 issqueezed out to both sides by 14.3 μm each. The radius of curvature ofthe adhesive 962 becomes 14.3 μm, and the maximum height of the adhesive962 is 14.3 μm. As described above, when the spacer 952 is adopted, theamount of squeezed-out excess can be reduced on both sides by 1.9 μmthan when the spacer 951 is adopted.

FIG. 17A is a perspective view indicative of a squeezed-out excess ofthe adhesive 962 of high viscosity when the spacer 953 is adopted.

FIG. 17B is a sectional view indicative of a squeezed-out excess of theadhesive 962 of high viscosity when the spacer 953 is adopted.

FIG. 17B is a sectional view indicated by a broken line II of FIG. 17A.In the present example, the length and width of the spacer 953 is 500 μmand 30 μm, respectively.

The radius of curvature of curved face of the bottom end is 13 μm, and aplanar face 953 b is arranged at the apex of the curved face with thewidth of 2 μm. When the spacer 953 is adopted, the adhesive 962 spreadsin a convex shape in the range of 59.8 μm having the spacer 953 in thecenter. In other words, the adhesive 962 is squeezed out to both sidesby 14.9 μm each. The radius of curvature of the adhesive 962 becomes14.9 μm, and the maximum height of the adhesive 962 is 14.9 μm. Asdescribed above, when the spacer 953 is adopted, the amount ofsqueezed-out excess can be reduced on both sides by 1.3 μm than when thespacer 951 is adopted.

Secondly, the amount of squeezed-out excess when the viscosity of theadhesive 962 is low is described.

FIG. 18A is a perspective view indicative of a squeezed-out excess ofthe adhesive 962 of low viscosity when the spacer 951 is adopted.

FIG. 18B is a sectional view indicative of a squeezed-out excess of theadhesive 962 of low viscosity when the spacer 951 is adopted.

FIG. 18B is a sectional view indicated by a broken line II of FIG. 18A.When the spacer 951 is adopted, the adhesive 962 spreads in a concaveshape in the range of 90.6 μm having the spacer 951 in the center. Inother words, the adhesive 962 is squeezed out to both sides by 30.3 μmeach. The radius of curvature of the adhesive 962 becomes 30.3 μm, andthe maximum height of the adhesive 962 is 30.3 μm.

FIG. 19A is a perspective view indicative of a squeezed-out excess ofthe adhesive 962 of low viscosity when the spacer 952 is adopted.

FIG. 19B is a sectional view indicative of a squeezed-out excess of theadhesive 962 of low viscosity when the spacer 952 is adopted.

FIG. 19B is a sectional view indicated by a broken line II of FIG. 19A.When the spacer 952 is adopted, the adhesive 962 spreads in a concaveshape in the range of 83.4 μm having the spacer 952 in the center. Inother words, the adhesive 962 is squeezed out to both sides by 26.7 μmeach. The radius of curvature of the adhesive 962 becomes 26.7 μm, andthe maximum height of the adhesive 962 is 26.7 μm. As described above,when the spacer 952 is adopted, the amount of squeezed-out excess can bereduced on both sides by 3.6 μm than when the spacer 951 is adopted.

FIG. 20A is a perspective view indicative of a squeezed-out excess ofthe adhesive 962 of low viscosity when the spacer 953 is adopted.

FIG. 20B is a sectional view indicative of a squeezed-out excess of theadhesive 962 of low viscosity when the spacer 953 is adopted.

FIG. 20B is a sectional view indicated by a broken line II of FIG. 20A.When the spacer 953 is adopted, the adhesive 962 spreads in a concaveshape in the range of 85.6 μm having the spacer 953 in the center. Inother words, the adhesive 962 is squeezed out to both sides by 27.8 μmeach. The radius of curvature of the adhesive 962 becomes 27.8 μm, andthe maximum height of the adhesive 962 is 27.8 μm. As described above,when the spacer 953 is adopted, the amount of squeezed-out excess can bereduced on both sides by 2.5 μm than when the spacer 951 is adopted.

Assuming that the speed of positioning is even when the spacers 951 to954 are bonded, the spacer 951 squeezes a greater amount of adhesivethan the other spacers, and the speed with which the adhesive 962 issqueezed out in the horizontal directions increases. For this reason, inactuality, the difference in the amount of squeezed-out excess isgreater than the calculated values as described above.

When the spacers 952 to 954 are adopted, the adhesive 962 enters thereduced portion with reference to the spacer 951. For this reason, theamount of squeezed-out excess in the horizontal directions can bereduced to zero depending on the amount of the adhesive 962 and theshapes of the spacers 952 to 954.

First Embodiment

A first embodiment of the present disclosure is described below. Thefirst embodiment of the present disclosure relates to an optical device1.

FIG. 21A is a top view of an optical device 1 according to a firstembodiment of the present disclosure.

FIG. 21B is a sectional view of the optical device 1 according to thefirst embodiment of the present disclosure.

FIG. 21C is a partially magnified view of the sectional view of FIG.21B.

FIG. 22A is a bottom view of the MLA substrate 101 according to thefirst embodiment of the present disclosure.

FIG. 22B is a sectional view of the MLA substrate 101 according to thefirst embodiment of the present disclosure.

FIG. 21B is a diagram illustrating a cross-sectional view along line I-Iof FIG. 21A.

FIG. 22B is a diagram illustrating a cross-sectional view along lineII-II of FIG. 22A.

As illustrated in FIG. 21A to FIG. 21C, FIG. 22A, and FIG. 22B, theoptical device 1 according to the first embodiment of the presentdisclosure is a laser-beam source module including the VCSEL arraysubstrate 110 and the MLA substrate 101. The VCSEL array substrate 110includes a plurality of VCSEL devices 110 a that are arranged on a topface 110 b. The MLA substrate 101 includes a base 101 c, a plurality ofmicrolenses 101 a, a spacer 101 b that extends in the Y-axis direction.The microlenses 101 a are arranged in a planar fashion so as tocorrespond to the array of the VCSEL devices 110 a. Each one of themicrolenses 101 a is disposed such that the optical axis “O” of therelevant one of the microlenses 101 a matches the central optical axisof the laser beam L that the facing one of the VCSEL 10 a emits. Thedistance z1 between the VCSEL array substrate 110 and the MLA substrate101 is adjusted such that the focal point of each of the microlenses 101a is aligned with the center of the light-emitting point of each of theVCSEL devices 110 a. In other words, the microlenses 101 a face theVCSEL devices 110 a, which serve as the light source, and are arrangedin line with the optical axes of the VCSEL devices 110 a. Due to thisconfiguration, each one of the microlenses 101 a can emit the laser beamL, which is emitted from the facing one of the VCSEL devices 110 a, as acollimated beam. The VCSEL array substrate 110 is an example of a firstsubstrate, and the MLA substrate 101 is an example of a secondsubstrate. The top face 110 b is an example of a first face, and theface of the base 101 c on which the microlenses 101 a are arranged is anexample of a second face. Each of the VCSEL devices 110 a is an exampleof a photo-electric element, and the spacer 101 b is an example of ajoint. The Y-axis direction is an example of a first direction. Notealso that the microlenses 101 a are not limited to collimator lenses,but may be any other kinds of lenses as long as long as they have afunction to change the direction in which the light travels such as afunction to concentrate or diverge the light, and to deflect the light.

The spacers 101 b are arranged on both sides of the MLA that is composedof the microlenses 101 a in the X-axis directions. The length of thespacers 101 b in the Y-axis direction is longer than the length of eachone of the microlens array that is composed of the multiple microlenses101 a in the Y-axis direction. The spacers 101 b has a certain heightthat is higher than the height of each one of the microlenses 101 a,with reference to the face of the MLA substrate 101 on which themicrolenses 101 a are arranged. For example, the sum of the distance z1and the height of each one of the microlenses 101 a is approximatelyequal to the height of the spacers 101 b with reference to the face ofthe MLA substrate 101 on which the microlenses 101 a are arranged. In asimilar manner to the spacer 952 as described above, the bottom end ofthe rectangular shape of each of the spacers 101 b is chamfered, andeach of the spacers 101 b has a shape in cross section where an obliqueface 101 e that is connected to a bottom face 101 d is formed. In otherwords, each one of the spacers 101 b includes the bottom face 101 d thatcontacts the top face 110 b, and the oblique face 101 e that is on aside closer to the face of the MLA substrate 101, on which themicrolenses 101 a are arranged, than the bottom face 101 d, and is apartfrom the top face 110 b. In other words, the face of each of the spacers101 b viewable from the VCSEL array substrate 110 side includes thebottom face 101 d that contacts the top face 110 b, and the oblique face101 e that is recessed towards the face of the MLA substrate 101, onwhich the microlenses 101 a are arranged, with reference to the bottomface 101 d. As described above, each of the spacers 101 b has an obliqueshape in which the sectional size on the MLA substrate 101 side isgreater than the sectional size on the bonding interface side. Thebottom face 101 d is an example of a first part, and the oblique face101 e is an example of a second part.

The size of the microlenses 101 a can be adjusted according to, forexample, the specification related to the size and optical properties(such as focal length, a spot diameter, and brightness) of the VCSELdevices 110 a and the tolerance.

The MLA substrate 101 is made of a transparent material for the laserbeams L that are emitted from the VCSEL devices 110 a. For example, itis desired that the material of the MLA substrate 101 be glass in viewof, for example, the heat generated by the laser beams L. In particular,it is desired that the MLA substrate 101 be made of B7 glass so as toreduce the difference in expansion rate Between the MLA substrate 101and the VCSEL array substrate 110. The spacer 101 b can be moldedintegrally with the base 101 c and the microlenses 101 a. In otherwords, the spacers 101 b may be made of the same material as the MLAsubstrate 101.

The VCSEL array substrate 110 is described below in detail.

FIG. 23 is a sectional view of the VCSEL array substrate 110 accordingto the first embodiment of the present disclosure.

As illustrated in FIG. 23, the multiple VCSEL devices 110 a are arrayedon the face of the VCSEL array substrate 110 on the submount substrate111 side. The multiple VCSEL devices 110 a are made on the substrate 141such as an n-GaAs substrate in a monolithic manner, and all the multipleVCSEL devices 110 a have the same membrane configuration. Each one ofthe VCSEL devices 110 a is, for example, a surface-emitting laser devicewhose oscillation wavelength is in the range around 940 nanometers (nm)(about +30 nm around 940 mm).

Each one of the VCSEL devices 110 a includes, for example, an-distributed Bragg reflector (DBR) 143 on the substrate 141 such as ann-GaAs substrate, a spacer layer 144, an active layer 145, a spacerlayer 146, a p-DBR 147, and a to-be-selected oxidized layer 151. Theto-be-selected oxidized layer 151 includes an oxidized area 151 a and anon-oxidized area 151 b. The refractive index of the n-GaAs substrate isabout 3.5.

The n-DBR 143 is formed on the substrate 141. The n-DBR 143 is, forexample, a semiconducting multilayer reflector consisting of a pluralityof n-type semiconductor films that are multilayered. The n-DBR 143includes, for example, a low refractive index layer that is composed ofn-Al0.9Ga0.1As and a high refractive index layer composed ofn-Al_(0.2)Ga_(0.8)As. The n-DBR 143 includes, for example, thirty pairsof low refractive index layer and high refractive index layer.

Between two layers of the n-DBR 143 that have varying refractiveindexes, for example, a gradient-composition layer with the thickness of20 nm where the composition gradually changes from a side of thecomposition to the other side of the composition is provided in order toreduce the electrical resistance. Each of the layers of varyingrefractive indexes is designed to include one-half of the adjacentgradient-composition layer and have the optical thickness of λ/4 when itis assumed that the oscillation wavelength is λ. Note that when theoptical thickness is λ/4, the actual thickness of the layer is D=λ/4n(where n denotes the refractive index of the medium of that layer).

The spacer layer 144 is formed on the n-DBR 143. For example, the spacerlayer 144 is a non-doped AlGaInP layer.

The active layer 145 is formed on the spacer layer 144. The active layer145 has a triple-bond quantum well structure including, for example,three quantum well layers and four barrier layers. Those quantum welllayers are composed of, for example, InGaAs, and those barrier layersare composed of, for example, AlGaAs.

The spacer layer 146 is formed on the active layer 145. For example, thespacer layer 146 is a non-doped AlGaInP layer.

The area that includes the spacer layer 144, the active layer 145, andthe spacer layer 146 is referred to as a resonator structure (resonatorarea), and is designed to include one-half of the adjacentgradient-composition layer and have the optical thickness of onewavelength (λ). The active layer 145 is disposed in the center of theresonator structure so as to achieve a high stimulated-emission rate.Note that the center of the resonator structure corresponds to a bellyof the standing-wave distribution of the electric field.

The p-DBR 147 is formed on the spacer layer 146. The p-DBR 147 is, forexample, a semiconducting multilayer reflector consisting of a pluralityof p-type semiconductor films that are multilayered. The p-DBR 147includes, for example, a low refractive index layer that is composed ofp-Al_(0.9)Ga_(0.1)As and a high refractive index layer composed ofp-Al_(0.2)Ga_(0.8)As. The p-DBR 147 includes, for example, twenty pairsof low refractive index layer and high refractive index layer.

Between two layers of the p-DBR 147 that have varying refractiveindexes, for example, a gradient-composition layer with the thickness of20 nm where the composition gradually changes from a side of thecomposition to the other side of the composition is provided in order toreduce the electrical resistance. Each of the layers of varyingrefractive indexes is designed to include one-half of the adjacentgradient-composition layer and have the optical thickness of 714 when itis assumed that the oscillation wavelength is λ.

The to-be-selected oxidized layer 151 that is composed of, for example,p-AlAs is inserted to the p-DBR 147 with the thickness of, for example,30 nanometers (nm). For example, the position to which to-be-selectedoxidized layer 151 is to be inserted may be within the second pair of ahigh refractive index layer and a low refractive index layer whencounted from the spacer layer 146. The to-be-selected oxidized layer 151may include a layer such as a gradient-composition layer and anintermediate layer on the upper side and underside. In the presentembodiment, the term selective oxidized layer collectively includes alayer that is actually oxidized.

The p-DBR 147, the spacer layer 146, the active layer 145, the spacerlayer 144, and a part of the n-DBR 143 are removed by etching, and as aresult, a plurality of mesas 150 that correspond to the VCSEL devices110 a, respectively, are formed.

An insulating layer 153 is formed to cover each of the mesas 150. Forexample, SiN, SiON, and SiO₂ may be used as materials for the insulatinglayer 153. An aperture 154 that exposes a part of the p-DBR 147 on thetop of each of the mesas 150, and an aperture 156 that exposes a part ofthe n-DBR 143 at the bottom of the trench between a neighboring pair ofmesas 150 are formed on the insulating layer 153.

A p-side electrode 155 that is electrically connected to the p-DBR 147through the aperture 154 is independently formed on the insulating layer153 for each one of the mesas 150. For example, a multilayered film inwhich titanium (Ti), platinum (Pt), and gold (Au) in the order listedfrom the p-DBR 147 side are stacked on top of each other may be used asthe p-side electrode 155.

An n-side electrode 157 that is electrically connected to the n-DBR 143through an aperture 156 is formed on the insulating layer 153. Forexample, a multilayered film in which gold-germanium (AuGe) alloy,nickel (Ni), and gold (Au) are stacked on top of each other in the orderlisted from the n-DBR 143 side may be used as the n-side electrode 157.

An n-contact layer such as n-GaAs layer may be arranged between then-side electrode 157 and the n-DBR 143, and a p-contact layer such as ap-GaAs layer may be arranged between the p-side electrode 155 and thep-DBR 147.

In the VCSEL array substrate 110, light is emitted at the light-emittingpoints 148 of the multiple VCSEL devices 110 a, and laser beams areemitted from the substrate 141 side.

As described above, the oscillation wavelength of the multiple VCSELdevices 110 a is in a 940 nm band (about ±30 nm around 940 mm). Some ofthe wavelengths that are absorbed by the air of the earth is included inthis wavelength range, and if such wavelengths are applied to, forexample, a range sensor that uses laser beams to measure distance, asystem with low noise can be configured. In this wavelength range, theabsorption coefficient of ytterbium (Yb)-doped yttrium aluminum garnet(YAG) solid laser is high, and the Yb-doped YAG solid laser canefficiently be pumped or activated. The indium gallium arsenide (InGaAs)that is used for the quantum well layer of the active layer 145 hascompression strain for gallium arsenide (GaAs), and each one of themultiple VCSEL devices 110 a has a high differential gain (DG). For thisreason, the VCSEL array substrate 110 can oscillate at a low threshold,and the VCSEL array substrate 110 has a high level of efficiency inlight transformation. Note also that InGaAs does not includechemically-active Al. For this reason, the very small quantity of oxygenincluded in a reaction chamber during crystal growth cannot easily betaken in the active layer 145. Accordingly, high reliability can also beachieved.

The refractive index of the n-GaAs substrate is about 3.5. For thisreason, when the outside of the substrate 141, which is an exit plane,is airspace, the light that is emitted from the light-emitting point 148is refracted at the boundary between the substrate 141 and the air(refractive index n=1.0), and the angle of radiation of the laser beamincreases. The microlenses 101 a are arranged so as to correspond to themultiple VCSEL devices 110 a, and the angle of radiation of the laserbeam is controlled to a desired angle. As the angle of radiation of thelaser beam is controlled, the spot diameter can be shortened when thelaser beams that have passed through the microlenses 101 a areconcentrated onto an object through a condenser lens or the like.

As illustrated in FIG. 21C, a bottom face 101 d of each of the spacers101 b contacts the top face 110 b of the VCSEL array substrate 110, andthe adhesive 120 is arranged around the contacting region. The spacers101 b and the VCSEL array substrate 110 are bonded together by theadhesive 120. At least, the adhesive 120 is arranged between the obliqueface 101 e and the top face 110 b. In a planar view, the adhesive 120may be squeezed out to an external area of each of the spacers 101 b.The adhesive 120 may be spread out to an inner area of each of themicrolenses 101 a. However, the adhesive 120 does not reach an area ofthe VCSEL array substrate 110 through which light is emitted.Accordingly, the optical properties are not impaired.

A method of manufacturing the optical device 1 according to the firstembodiment of the present disclosure is described below.

FIG. 24 is a flowchart of a method of manufacturing the optical device 1according to the first embodiment of the present disclosure.

Firstly, the VCSEL array substrate 110 is made (step S11), and asubmount substrate 111 is prepared for the housing (step S12). Then, theVCSEL array substrate 110 is implemented on the submount substrate 111(step S13). A known method such as soldering may be used for the aboveimplementation.

The MLA substrate 101 is made in a separate manner (step S14). Forexample, the MLA substrate 101 may be made by glass imprinting oretching. In view of the productivity, glass imprinting is morepreferable.

Either one of the making of the MLA substrate 101 and the assembly ofthe VCSEL array substrate 110 and the submount substrate 111 may be doneearlier than the other. Alternatively, the making of the MLA substrate101 and the assembly of the VCSEL array substrate 110 and the submountsubstrate 111 may be done at the same time.

Subsequently, the assembly of the VCSEL array substrate 110 and thesubmount substrate 111 is implemented on a device to be implemented, andthe adhesive 120 is applied to such a device to be implemented (stepS15).

FIG. 25A is a top view of the applied adhesive 120 according to thefirst embodiment of the present disclosure.

FIG. 25B is a sectional view of the applied adhesive 120 according tothe first embodiment of the present disclosure.

FIG. 25B is a diagram illustrating a cross-sectional view along line I-Iof FIG. 25A. As illustrated in FIG. 25A and FIG. 25B, the adhesive 120is applied to an area to which the spacers 101 b of the VCSEL arraysubstrate 110 is to be bonded. The materials of the adhesive 120 may beselected depending on, for example, the way of bonding and the materialsof the VCSEL array substrate 110. For example, screen printing isadopted, and the VCSEL array substrate 110 may be pattern-coated withsilver (Ag) paste. The MLA substrate 101 is implemented on a device tobe implemented in a separate manner (step S16).

Then, the relative positions of the MLA substrate 101 and the assemblyof the VCSEL array substrate 110 and the submount substrate 111 areadjusted with a high degree of precision, and the MLA substrate 101 andthe assembly of the VCSEL array substrate 110 and the submount substrate111 are bonded together (step S17). Finally, the manufacturing of theoptical device 1 is complete after the inspection (step S18).

The VCSEL array substrate 110 may be conductively connected to an ICpackage before or after the bonding processes of the MLA substrate 101.When the VCSEL array substrate 110 is conductively connected to an ICpackage after the bonding processes of the MLA substrate 101, such anelectrical conduction can be implemented by performing, for example,known wire bonding from an edge of the VCSEL array substrate 110.

According to the first embodiment of the present disclosure, the crosssection of each of the spacers 101 b has an oblique shape at the frontend such that the area of the joint will be small. Due to such aconfiguration, the adhesive 120 stays at an inclined portion, and theamount of the spread of the adhesive 120 can be controlled. As describedabove, according to the first embodiment of the present disclosure, theadhesive 120 can be prevented from being spread out and reaching theoptically-effective regions such as the lens units of the MLA substrate101 or the light-emitting units of the VCSEL array substrate 110. As thecross-sectional area of the front end of each of the spacers 101 b issmaller than that of the root end, the adhesive 120 can be squeezed outto the sides of the spacers 101 b in a gradual manner, and thevariations in the amount of the spread of the adhesive 120 and theirregularities of the spread of the adhesive 120 in a planar view can bereduced. For this reason, when the distance between the optical area andthe bonding area is designed in view of the variations in and the sizeof the spread of the adhesive 120 at the time of bonding, such distancecan be shortened.

Each of the spacers 101 b maintains the distance between the multipleVCSEL devices 110 a and the multiple microlenses 101 a at a constantvalue. As a result, desired optical properties can be achieved, and theoptical device 1 (laser-beam source module) can be downsized.

Alternatively, the microlenses 101 a may be arranged on the other sideof the VCSEL array substrate 110, instead of being arranged on the faceof the MLA substrate 101 on the VCSEL array substrate 110 side.Alternatively, the microlenses 101 a may be arranged both on the face ofthe MLA substrate 101 on the VCSEL array substrate 110 side and on theother side of the VCSEL array substrate 110.

In the VCSEL array substrate 110, the multiple VCSEL devices 110 a maybe configured to emit light from the other side of the substrate 141. Inother words, the multiple VCSEL devices 110 a may be configured to emitlight from the mesas 150 side.

The number of spacers 101 b is not limited to any specific value. Theplanar shape of each of the spacers 101 b may have a shape other thanthe rectangular shape as long as it has longitudinal sides. In thepresent embodiment, the optical axis of the VCSEL device and the opticalaxis of the corresponding microlens are arranged such that those opticalaxes match. However, no limitation is intended thereby, and it may bearranged such that the laser beams that are emitted from a plurality ofVCSEL devices are incident on a single microlens, or the optical axis ofthe VCSEL device and the optical axis of the corresponding microlens maybe arranged such that those optical axes are shifted and made differentfrom each other.

Modification of First Embodiment

A first modification of the first embodiment of the present disclosureis described below. The modification of the first embodiment of thepresent disclosure the shape in cross section of the spacers 101 b isdifferent from the first embodiment in the respect that XXX.

FIG. 26A is a top view of the optical device 1 according to amodification of the first embodiment of the present disclosure.

FIG. 26B is a sectional view of the optical device 1 according to amodification of the first embodiment of the present disclosure.

FIG. 27A is a bottom view of the MLA substrate 101 according to themodification of the first embodiment of the present disclosure.

FIG. 27B is a sectional view of the MLA substrate 101 according to amodification of the first embodiment of the present disclosure.

FIG. 26B is a diagram illustrating a cross-sectional view along line I-Iof FIG. 26A. FIG. 27B is a diagram illustrating a cross-sectional viewalong line II-II of FIG. 27A.

As illustrated in FIG. 26A, FIG. 26B, FIG. 27A, and FIG. 27B, in asimilar manner to the spacer 953 as described above, each one of thespacers 101 b according to the present modification of the firstembodiment described above has a shape in cross section where aspherically curved face 101 f is formed at the bottom end of therectangular shape. A planar face 101 g is arranged at the apex of thecurved face 101 f with the width of a few or several micrometers (μm).In other words, each one of the spacers 101 b includes the planar face101 g that contacts the top face 110 b, and the spherically curved face101 f that is disposed on a side closer to the face of the MLA substrate101, on which the microlenses 101 a are arranged, than the planar face101 g, and thus is apart from the top face 110 b. In other words, theface of each of the spacers 101 b viewable from the VCSEL arraysubstrate 110 side includes the planar face 101 g that contacts the topface 110 b, and a curved face 101 f that has spherical surface and isrecessed towards the face of the MLA substrate 101, on which themicrolenses 101 a are arranged, with reference to the planar face 101 g.As described above, the cross-sectional shape of each of the spacers 101b has a curved shape in which the size on the MLA substrate 101 side isgreater than the size on the bonding interface side. The planar face 101g is an example of a first part, and the curved face 101 f is an exampleof a second part.

The other aspects of the configuration according to the presentembodiment are equivalent to those of the first embodiment as describedabove.

Also with such a modification of the first embodiment of the presentdisclosure, advantageous effects similar to those of the firstembodiment as described above can be achieved.

Alternatively, the arrangement of the planar face 101 g may be omitted.In such cases, the apex of the curved face 101 f is an example of afirst part.

Like the spacer 954, each of the spacers 101 b may have a shape in crosssection where a step is formed at the bottom end of the rectangularshape and a side face that is connected to a bottom face is formed. Insuch cases, the bottom face is an example of a first part, and thebottom face of the step continuous to the side faces is an example of asecond part.

Second Embodiment

A second embodiment of the present disclosure is described below. In thefirst embodiment of the present disclosure, the optical device 1 ismanufactured as the VCSEL array substrate 110 that is chipped and theMLA substrate 101 that is chipped are bonded together. By contrast, inthe second embodiment of the present disclosure, a wafer including aplurality of VCSEL array substrates 110 and a wafer including aplurality of MLA substrates 101 are bonded together, and dicing isperformed after the bonding. The optical device 2 according to thesecond embodiment of the present disclosure is manufactured as describedabove, and is different from the optical device of the first embodimentin regard to the structure.

FIG. 28A is a plan view of the optical device 2 according to the secondembodiment of the present disclosure.

FIG. 28B is a sectional view of the optical device 2 according to thesecond embodiment of the present disclosure.

FIG. 29A is a bottom view of the MLA substrate 101 according to thesecond embodiment of the present disclosure.

FIG. 29B is a sectional view of the MLA substrate 101 according to thesecond embodiment of the present disclosure.

FIG. 28B is a diagram illustrating a sectional view along line I-I ofFIG. 28A. FIG. 29B is a diagram illustrating a cross-sectional viewalong line II-II of FIG. 29A.

As illustrated in FIG. 28A, FIG. 28B, FIG. 29A, and FIG. 29B, in theoptical device 2 according to the second embodiment of the presentdisclosure, the spacer 201 b is arranged to surround all directions ofthe MLA. In other words, the spacer 201 b includes a pair of elements onboth sides of the MLA in the X-axis directions and a pair of elements onboth sides of the MLA in the Y-axis directions, and these four elementsare joined together. Accordingly, a single spacer 201 b is formed in acircular shape. The spacer 201 b has a shape in cross section similar tothat of the spacer 101 b. In other words, the bottom end of therectangular shape of the spacer 201 b according to the second embodimentof the present disclosure is chamfered, and the spacer 201 b has a shapein cross section where an oblique face 201 e that is connected to abottom face 201 d is formed. The bottom face 201 d is an example of afirst part, and the oblique face 201 e is an example of a second part.

The bottom face 201 d of the spacer 201 b contacts the top face 110 b ofthe VCSEL array substrate 110, and the adhesive 220 is arranged aroundthe contacting region. In a similar manner to the spacer 201 b, theadhesive 220 is arranged in a circular shape in a planar view. Thespacers 201 b and the VCSEL array substrate 110 are bonded together bythe adhesive 220. At least, the adhesive 220 is arranged between theoblique face 201 e and the top face 110 b. In a planar view, theadhesive 220 may be squeezed out to an external area of each of thespacers 201 b.

In a planar view, the frame of the VCSEL array substrate 110 and theframe of the base 101 c of the MLA substrate 101 are in line with theframe on the submount substrate 111.

The other aspects of the configuration according to the presentembodiment are equivalent to those of the first embodiment as describedabove.

A method of manufacturing the optical device 2 according to the secondembodiment of the present disclosure is described below.

FIG. 30 is a flowchart of a method of manufacturing the optical device 2according to the second embodiment of the present disclosure.

FIG. 31 is a bottom view of an MLA substrate 261 of large format,according to the second embodiment of the present disclosure.

FIG. 32A is a top view of the adhesive 220 according to the secondembodiment of the present disclosure.

FIG. 32B is a sectional view of the adhesive 220 according to the secondembodiment of the present disclosure.

FIG. 32B is a diagram illustrating a sectional view along line I-I ofFIG. 32A. FIG. 32A illustrates the elements that correspond to a singleoptical device 2.

FIG. 33A to FIG. 33C are sectional views illustrating a method ofmanufacturing the optical device 2 according to the second embodiment ofthe present disclosure.

Firstly, a VCSEL array substrate 210 of large format (see FIG. 32A andFIG. 32B) is made (step S21), and a submount substrate 211 of largeformat (see FIG. 32B) is prepared for the housing (step S22). Aplurality of VCSEL array substrates 110 that are not-yet chipped arearranged on the VCSEL array substrate 210. The same number of submountsubstrates 111, which are not-yet chipped, as the multiple VCSEL arraysubstrates 110 included in the VCSEL array substrate 210 are arranged onthe submount substrate 211. Then, the VCSEL array substrate 210 isimplemented on the submount substrate 211 (step S23). When suchimplementation is performed, a known method such as soldering may beused.

The MLA substrate 261 of large format is made in a separate manner (stepS24). The same number of MLA substrates 101, which are not-yet chipped,as the multiple VCSEL array substrates 110 included in the VCSEL arraysubstrate 210 are arranged on the MLA substrate 261. For example, theMLA substrate 261 may be made by glass imprinting or etching. In view ofthe productivity, glass imprinting is more preferable.

Either one of the making of the MLA substrate 261 and the assembly ofthe VCSEL array substrate 210 and the submount substrate 211 may be doneearlier than the other. Alternatively, the making of the MLA substrate261 and the assembly of the VCSEL array substrate 210 and the submountsubstrate 211 may be done at the same time.

Subsequently, the assembly of the VCSEL array substrate 210 and thesubmount substrate 211 is implemented on a device to be implemented, andthe adhesive 220 is applied to such a device to be implemented (stepS25). As illustrated in FIG. 32A and FIG. 32B, the adhesive 220 isapplied to an area to which the spacers 101 b of the VCSEL arraysubstrate 210 is to be bonded. The adhesive 220 that is adopted in thesecond embodiment of the present application may be equivalent to theadhesive 120 that is adopted in the first embodiment of the presentapplication ad described above. The MLA substrate 261 is implemented ona device to be implemented in a separate manner (step S26).

Then, as illustrated in FIG. 33A, the relative positions of the MLAsubstrate 261 and the assembly of the VCSEL array substrate 210 and thesubmount substrate 211 are adjusted with a high degree of precision, andthen, as illustrated in FIG. 33B, the MLA substrate 261 and the assemblyof the VCSEL array substrate 210 and the submount substrate 211 arebonded together (step S27). Then, as illustrated in FIG. 33C, a dicingmachine is used to cut a composite of the assembly and the MLA substrate261 into separate pieces (step S28). Finally, the manufacturing of theoptical device 2 is complete after the inspection (step S29).

Before the MLA substrate 261 is implemented on the assembly of the VCSELarray substrate 210 and the submount substrate 211, the VCSEL arraysubstrate 210 is conductively connected to an IC package. This isbecause the VCSEL array substrate 210 is covered with the MLA substrate261 after the MLA substrate 261 is implemented. Once the VCSEL arraysubstrate 210 is covered with the MLA substrate 261, the VCSEL arraysubstrate 210 becomes physically inaccessible.

Also with the second embodiment of the present disclosure, advantageouseffects similar to those of the first embodiment as described above canbe achieved. In the second embodiment of the present disclosure, thespacer 201 b continuously surrounds the MLA in a planar view. Due tosuch a configuration, the cutting water that is used for dicing can beprevented from entering an optically-effective region.

Each of the spacers 201 b may have a curved face in cross section as inthe control sample of the first embodiment of the present disclosure, ormay have a step like the spacer 954.

Third Embodiment

A third embodiment of the present disclosure is described below. In thesecond embodiment, a wafer including a plurality of VCSEL arraysubstrates 110 and a wafer including a plurality of MLA substrates 101are bonded together, and dicing is performed after the bonding. In suchmethods, a part of the corners or sides of the MLA substrate 101 in aplanar view may be cracked or chipped when dicing is performed. Such acracking or the like may be referred to as chipping.

FIG. 34 is a sectional view illustrating chipping according to thesecond embodiment of the present disclosure. chipping

When dicing is performed, excessive stress tends to be applied to, forexample, some of the corners of the MLA substrate 101, and the chipping270 is caused by such stress. By contrast, in the third embodiment ofthe present disclosure, dicing is performed while controlling orreducing the stress that could be applied to, for example, some of thecorners of the MLA substrate 101. The optical device 3 according to thethird embodiment of the present disclosure, which is produced as above,is different from the optical device of the second embodiment in regardto the structure.

FIG. 35 is a sectional view of the optical device 3 according to thethird embodiment of the present disclosure.

As illustrated in FIG. 35, in the optical device 3 according to thethird embodiment of the present disclosure, spacers 301 b are formed asdicing is performed in the center of the width direction of the portionthat corresponds to the spacer 201 b according to the second embodimentof the present disclosure. Due to this configuration, a bottom side ofeach of the spacers 301 b contacts the top face 110 b of the VCSEL arraysubstrate 110 throughout the outer regions of the optical device 3. Ifthere is a point where each of the spacers 301 b contacts the top face110 b of the VCSEL array substrate 110 in at least some of the outerregions of the optical device 3, the further spread of chipping can beprevented effectively when chipping occurs at a non-contacting part. Itis more desirable if the spacers 301 b are arranged such that each ofthe spacers 301 b contacts the top face 110 b of the VCSEL arraysubstrate 110 at the corners of the optical device 3 where stress tendsto occur. With the optical device 3 according to the third embodiment ofthe present disclosure, the spacers 301 b are arranged such that each ofthe spacers 301 b contacts the top face 110 b of the VCSEL arraysubstrate 110 throughout the outer regions of the optical device 3. Dueto this configuration, the chances of chipping can be reduced moreeffectively.

The other aspects of the configuration according to the presentembodiment are equivalent to those of the second embodiment of thesecond embodiment of the present disclosure as described above.

Each of the spacers 301 b may have a curved face in cross section, ormay have a step in cross section like the spacer 954, as in the controlsamples of the first embodiment of the present disclosure.

A method of manufacturing the optical device 3 according to the thirdembodiment of the present disclosure is described below.

FIG. 36A is a bottom view of a part of the large-format MLA substrate361 used in the third embodiment of the present disclosure.

FIG. 36B is a sectional view of a part of the large-format MLA substrate361 used in the third embodiment of the present disclosure.

FIG. 36B is a diagram illustrating a sectional view along line of FIG.36A.

FIG. 37A to FIG. 37C are sectional views illustrating a method ofmanufacturing the optical device 3 according to the third embodiment ofthe present disclosure.

As illustrated in FIG. 36A and FIG. 36B, in the large-format MLAsubstrate 361 used in the third embodiment of the present disclosure, aspacer 361 b that is shared by the neighboring MLA substrates 101 isarranged. The spacer 361 b is placed on the dicing line, and the widthW2 of a bottom face 361 d of the spacer 361 b is wider than the width W1of the dicing blade.

In the third embodiment of the present disclosure, the MLA substrate 361is prepared, and in a similar manner to the second embodiment, theassembly of the VCSEL array substrate 210 and the submount substrate 211is implemented on a device to be implemented, and the adhesive 220 isapplied to such a device to be implemented. Then, as illustrated in FIG.37A, the relative positions of the MLA substrate 361 and the assembly ofthe VCSEL array substrate 210 and the submount substrate 211 areadjusted with a high degree of precision. Then, as illustrated in FIG.37B, the MLA substrate 361 and the assembly of the VCSEL array substrate210 and the submount substrate 211 are bonded together. Then, asillustrated in FIG. 37C, a composite of the assembly and the MLAsubstrate 361 is cut into separate pieces, using a dicing machine, alongthe center of the spacer 361 b in the width direction. Finally, themanufacturing of the optical device 3 is complete after the inspection.

In the third embodiment of the present disclosure, an MLA substrate iscut into separate pieces along the center of the spacer 361 b in thewidth direction. Accordingly, the sides of the spacer 361 b that appeardue to the cutting processes become contiguous with the VCSEL arraysubstrate 110. Due to this configuration, at least, each of the spacers361 b contacts the VCSEL array substrate 110 at some of the corners ofthe MLA substrate 101, and contacts the VCSEL array substrate 110 atsome of the outer region of the MLA substrate 101. Accordingly, theouter region that includes the corners of the MLA substrate 101 isprotected by the VCSEL array substrate 110 from the lower side, and thechances of chipping can be reduced.

Modification of Third Embodiment

A modification of the third embodiment of the present disclosure isdescribed below. The modification of the third embodiment of the presentdisclosure is different from the third embodiment in the respect thatthe modification of the third embodiment adopts a step cut method to cutan MLA substrate into separate pieces.

FIG. 38A to FIG. 38C are sectional views illustrating a method ofmanufacturing the optical device 3 according to a modification the thirdembodiment of the present disclosure.

In the modification of the third embodiment of the present disclosure,the MLA substrate 361 is prepared, and in a similar manner to the secondembodiment, the assembly of the VCSEL array substrate 210 and thesubmount substrate 211 is implemented on a device to be implemented, andthe adhesive 220 is applied to such a device to be implemented. Then, asillustrated in FIG. 38A, the relative positions of the MLA substrate 361and the assembly of the VCSEL array substrate 210 and the submountsubstrate 211 are adjusted with a high degree of precision, and then asillustrated in FIG. 38B, the MLA substrate 361 and the assembly of theVCSEL array substrate 210 and the submount substrate 211 are bondedtogether. Then, as illustrated in FIG. 37C, a dicing machine is used,and a composite of the assembly and the MLA substrate 361 is cut intoseparate pieces, using a step cut method, along the center of the spacer361 b in the width direction. In other words, the first dicing blade isused to cut the assembly into separate pieces, and then the seconddicing blade whose width is narrower (thinner) than the first dicingblade is used to cut the VCSEL array substrate 110 and the submountsubstrate 111 into separate pieces. For example, a dicing blade suitablefor cutting glass is used as the first dicing blade. For example, adicing blade suitable for cutting a compound semiconductor is used asthe second dicing blade. Finally, the manufacturing of the opticaldevice 3 is complete after the inspection.

In the present modification of the above embodiment, an MLA substrate iscut into separate pieces along the center of the spacer 361 b in thewidth direction. Accordingly, the sides of the spacer 361 b that appeardue to the cutting processes reach the VCSEL array substrate 110. Due tothis configuration, at least, each of the spacers 361 b contacts theVCSEL array substrate 110 at some of the corners of the MLA substrate101, and contacts the VCSEL array substrate 110 at some of the outerregion of the MLA substrate 101. Accordingly, the outer region thatincludes the corners of the MLA substrate 101 is protected by the VCSELarray substrate 110 from the lower side, and the chances of chipping canbe reduced. When the VCSEL array substrate 110 and the submountsubstrate 111 are cut into separate pieces using the second dicingblade, the outer region that includes the corners of the MLA substrate101 is kept protected by the VCSEL array substrate 110 from the lowerside.

When a step cut method is adopted, the first dicing blade can be used tocut the MLA substrate 361, and the second dicing blade can be used tocut the VCSEL array substrate 210 and the submount substrate 211. Thedominant materials for the MLA substrate 361 are differences from thedominant materials for the VCSEL array substrate 210 and the submountsubstrate 211. Due to this configuration, cutting processes can beperformed under more desirable conditions, and the chances of chippingcan be reduced with even greater reliability.

According to the third embodiment and the modification of the thirdembodiment of the present disclosure, the spacer 361 b is shared by theneighboring MLA substrates 101. Due to this configuration, compared withthe configuration according to the second embodiment of the presentdisclosure, the distance between the neighboring pair ofoptically-effective regions can be shortened. In other words, the widthW4 of the spacer 361 b at the base (see FIG. 37A and FIG. 38A) can bemade shorter than the distance W3 between the outer edges of theneighboring pair of spacers 201 b on the optically-effective region side(see, for example, FIG. 33A) in the second embodiment of the presentdisclosure. Due to such a configuration, the chip size of the opticaldevice can be reduced, or the number of chips that can be obtained fromone wafer can be increased. Moreover, the cost can be reduced as thenumber of obtainable chips increases.

Fourth Embodiment

A fourth embodiment of the present disclosure is described below. Theplanar shape of the spacer according to the fourth embodiment of thepresent disclosure is different from the planar shape of the spaceraccording to the second embodiment of the present disclosure.

FIG. 39A is a bottom view of the MLA substrate 101 according to thefourth embodiment of the present disclosure.

FIG. 39B is a sectional view of the MLA substrate 101 according to thefourth embodiment of the present disclosure.

More specifically, FIG. 39B is a diagram illustrating a cross-sectionalview along line II-II of FIG. 39A.

The optical device according to the fourth embodiment of the presentdisclosure includes an MLA substrate 461 in place of the MLA substrate101 according to the second embodiment of the present disclosureprovided with the spacers 101 b whose planar shape is square-shaped. TheMLA substrate 461 is provided with a spacer 461 b that continuouslysurrounds a microlens array composed of a plurality of microlenses 101a. The spacer 461 b has a square shape in a planar view where the fourcorners are rounded. In other words, the planar shape of the outer edgeof the spacer 461 b is rounder than the planar shape of the MLAsubstrate 461.

In a similar manner to the modification of the first embodimentdescribed above, the spacer 461 b has a curved face on the bottom side.However, no limitation is indicated thereby, and an oblique face may beformed like the first embodiment of the present disclosure, or a stepmay be formed like the spacer 954.

The other aspects of the configuration according to the presentembodiment are equivalent to those of the second embodiment of thesecond embodiment of the present disclosure as described above.

Also with the fourth embodiment of the present disclosure, advantageouseffects similar to those of the second embodiment as described above canbe achieved.

As known in the art, the expansion rate of an MLA substrate is differentfrom the expansion rate of a VCSEL array substrate. For this reason,when the temperature changes in a state where these elements arecombined together, the force that prevents the expansion and contractionof these elements is caused near the joint. Thermal expansion or thermalcontraction is caused, for example, when bonding processes are performedat high temperature and when the completed optical device is used underhigh-temperature environments of 100 degrees Celsius ° C. orlow-temperature environments of −40 degrees Celsius ° C. Moreover, at aportion where the distance to the center of the optical device islonger, the amount of displacement due to thermal expansion or thermalcontraction in the relative positions of the MLA substrate and the VCSELarray substrate is greater, and the force that prevents thedisplacement, which is caused near the joint, is greater.

In the fourth embodiment of the present disclosure, the four corners ofthe spacer 461 b are rounded. For this reason, the distance between thecenter of the MLA substrate 461 and the four corners is shorter than thedistance between the center of the MLA substrate 101 and the fourcorners according to the second embodiment of the present disclosure.Accordingly, the maximum stress that could be applied to the joint whenthe temperature changes can be reduced, and the chances of exfoliationor peeling off due to thermal stress can be reduced.

First Modification of Fourth Embodiment

A first modification of the fourth embodiment of the present disclosureis described below. The planar shape of the spacer 101 b according tothe first modification of the fourth modification of the presentdisclosure is different from the planar shape of the spacer 101 baccording to the fourth embodiment of the present disclosure.

FIG. 40A is a bottom view of the MLA substrate 461 according to thefirst modification of the fourth embodiment of the present disclosure.

FIG. 40B is a sectional view of the MLA substrate 461 according to thefirst modification of the fourth embodiment of the present disclosure.

More specifically, FIG. 40B is a diagram illustrating a cross-sectionalview along line II-II of FIG. 40A.

In the first modification of the fourth embodiment of the presentdisclosure, the spacer 461 b has a square shape in a planar view wherethe four corners are, for example, chamfered. In other words, also inthe first modification of the first embodiment of the presentdisclosure, the planar shape of the outer edge of the spacer 461 b isrounder than the planar shape of the MLA substrate 461.

In the first modification of the fourth embodiment of the presentdisclosure, the four corners of the spacer 461 b are, for example,chamfered. For this reason, the distance between the center of the MLAsubstrate 461 and the four corners is shorter than the distance betweenthe center of the MLA substrate 101 and the four corners according tothe second embodiment of the present disclosure. Accordingly, themaximum stress that could be applied to the joint when the temperaturechanges can be reduced, and the chances of exfoliation or peeling offdue to thermal stress can be reduced.

Second Modification of Fourth Embodiment

A second modification of the fourth embodiment of the present disclosureis described below. The planar shape of the spacer according to thesecond modification of the fourth embodiment of the present disclosureis different from the planar shape of the spacer according to the fourthembodiment of the present disclosure.

FIG. 41A is a bottom view of the MLA substrate 461 according to thesecond modification of the fourth embodiment of the present disclosure.

FIG. 41B is a sectional view of the MLA substrate 101 according to thesecond modification of the fourth embodiment of the present disclosure.

More specifically, FIG. 41B is a diagram illustrating a cross-sectionalview along line II-II of FIG. 41A.

In the second modification of the fourth embodiment of the presentdisclosure, the spacer 461 b has a perfectly-circular doughnut-shapedplanar shape. In other words, also in the second modification of thefourth embodiment of the present disclosure, the planar shape of theouter edge of the spacer 461 b is rounder than the planar shape of theMLA substrate 461. The number of the microlenses 101 a and the number ofthe VCSEL devices 110 a may be smaller than those of the secondembodiment of the present disclosure. The spacer 461 b may have anelliptical doughnut-shaped planar shape.

In the second modification of the embodiments of the present disclosure,the spacer 461 b has a doughnut-shaped planar shape. For this reason,the distances from the center of the MLA substrate 461 to each part ofthe spacer 461 b is shorter than the distance between the center of theMLA substrate 101 and the four corners according to the secondembodiment of the present disclosure. Accordingly, the maximum stressthat could be applied to the joint when the temperature changes can bereduced, and the chances of exfoliation or peeling off due to thermalstress can be reduced.

The photo-electric element is not limited to a light-emitting element,but a light receiver such as a solid-state image sensing device may beused as a photo-electric element.

Fifth Embodiment

A fifth embodiment of the present disclosure is described below. Thefifth embodiment of the present disclosure relates to the light-sourcedevice 11 provided with an optical device (laser-beam source module)according to one of the first to fourth embodiments (and modificationsof these embodiments) of the present disclosure and a detector.

FIG. 42 is a diagram illustrating a schematic configuration of thedistance-measuring apparatus 10 as an example of detector.

The distance-measuring apparatus 10 includes a light-source device 11.The distance-measuring apparatus 10 is a distance detector that adopts atime-of-flight (TOF) method. More specifically, the distance-measuringapparatus 10 controls the light-source device 11 to emit pulsed lighttowards an object to be detected 12, and uses a light receiver 13 toreceive the light reflected from the object to be detected 12. Then, thedistance-measuring apparatus 10 measures the distance to the object tobe detected 12 based on the length of time it took to receive thereflected light

As illustrated in FIG. 42, the light-source device 11 includes a lightsource 14 and an optical system 15. The light source 14 is provided witha surface-emitting laser device according to one of the first to fourthembodiments of the present disclosure, and its light emission iscontrolled as an electric current is sent from the light source driver16. When the light source 14 is controlled to emit light, the lightsource driver 16 sends a signal to the signal control circuit 17. Theoptical system 15 includes an optical element such as a lens, adiffractive-optical element, and a prism that adjusts the divergenceangle or direction of the light emitted from the light source 14, andirradiates an object to be detected 12 with the light.

The light that is emitted from the light-source device 11 and thenreflected by the object to be detected 12 is guided to the lightreceiver 13 through the light-receptive optical system 18 that has alight-concentrating function. The light receiver 13 includes aphotoelectric conversion element. The light that is received by thelight receiver 13 is photoelectrically converted by the photoelectricconversion element, and the photoelectrically-converted light is sent tothe signal control circuit 17 as an electrical signal. The signalcontrol circuit 17 calculates the distance to the object to be detected12 based on the time difference between the timing of light emission(i.e., the timing at which a flash signal is input from the light sourcedriver 16) and the timing of light reception (i.e., the timing at whicha light signal is input from the light receiver 13). Accordingly, in thedistance-measuring apparatus 10, the light-receptive optical system 18and the light receiver 13 serve as a detection system on which the lightthat is emitted from the light-source device 11 and then reflected bythe object to be detected 12 is incident. The signal control circuit 17may be configured so as to obtain, for example, the information aboutthe presence or absence of the object to be detected 12 and the relativevelocity of the object to be detected 12, based on a signal sent fromthe light receiver 13.

Sixth Embodiment

A sixth embodiment of the present disclosure is described below. Thesixth embodiment relates to a distance-measuring apparatus 400. Thedistance-measuring apparatus 400 is an example of optical device.

FIG. 43 is a diagram illustrating a configuration of thedistance-measuring apparatus 400 according to the sixth embodiment ofthe present disclosure.

The distance-measuring apparatus 400 according to the sixth embodimentof the present disclosure includes a light-emitting unit 410, a lightreceiver 420, a timing circuit 430, and a control circuit 440.

For example, the light-emitting unit 410 includes a light source 411, alight source driver 412, an optical scanner 413, a scanner driver 414, ascanning-angle monitor 415, and a projection lens 416. The light source411 is provided with an optical device (laser-beam source module)according to one of the first to fourth embodiments (and modificationsof these embodiments) of the present disclosure. The light source driver412 drives the light source 411 based on the driving signal output fromthe control circuit 440. The optical scanner 413 includes, for example,a micro-electromechanical systems (MEMS) mirror or a polygon mirror. Thescanner driver 414 drives the optical scanner 413 based on the drivingsignal output from the control circuit 440. The vertical-cavitysurface-emitting lasers (VCSEL) module of the light source 411 includesa plurality of sub-light-emitting areas. Each one of the multiplesub-light-emitting areas includes at least one VCSEL device, and theVCSEL devices of each one of the multiple sub-light-emitting areas areelectrically connected to each other in parallel. The multiplesub-light-emitting areas are one-dimensionally arranged in thesub-scanning direction of the optical scanner 413, and can be driven inan individual manner. For example, the light source driver 412 drivesthe vertical-cavity surface-emitting lasers (VCSEL) module of the lightsource 411 with pulse current on the order of nanoseconds (ns). Thelaser beams that are emitted from the VCSEL device are converted intothe light of desired beam profile, where appropriate, by the projectionlens 416 or the like. Then, the irradiation direction of the light isdetermined by the optical scanner 413, and the light is emitted to theoutside of the distance-measuring apparatus 400. The scanning angle ofthe optical scanner 413 is measured by the scanning-angle monitor 415,and the result of such measurement is output to the control circuit 440.Each one of the optical scanner 413 and the projection lens 416 is anexample of a second optical element.

The laser beams that are emitted to the outside of thedistance-measuring apparatus 400 are reflected by an object, and returnto the distance-measuring apparatus 400 and reaches the light receiver420.

For example, the light receiver 420 includes a light receiver 421, alight-receptive lens 422, and a band-pass filter 423. The light receiver421 includes an avalanche photodiode (APD) device made of silicon (Si).The light-receptive lens 422 makes the light that has reached the lightreceiver 420 converge to the light receiver 421. The band-pass filter423 includes a dielectric multilayer, and is designed to let only thelight of oscillation wavelength of the light source 411 pass Due to theband-pass filter 423, the signal-to-noise (SN) ratio of signals can beimproved.

The light that has reached the light receiver 421 is converted into anelectrical signal by the light receiver 421, and is input to the timingcircuit 430 through an amplifier and a comparator 432. The electricalsignal may be processed by the amplifier 431 or the comparator 432 on anas-needed basis.

A driving signal for the light source 411 that is output from thecontrol circuit 440 and a signal that is sent from the light receiver421 are input to the timing circuit 430. The timing circuit 430calculates the delay time between these two kinds of signals, andoutputs the result of calculation to the control circuit 440.

The control circuit 440 obtains the information about the distance to anobject to be detected, based on a result of conversion performed on thedelay time sent from the timing circuit 430.

According to the distance-measuring apparatus 400 as described above,the distance to the object is measured, and laser beams are sequentiallyemitted to the sub-light-emitting areas of a VCSEL module and theregions of space that are split by the optical scanner 413. Due to thisconfiguration, two-dimensional distance information can be obtained. Forexample, this distance-measuring apparatus 400 may be used for lightdetection and ranging (LiDAR).

An electronic device may be controlled based on the information obtainedfrom a detector according to at least one of the above embodiments ofthe present disclosure. For example, such an electronic device may be aninformation terminal, or a movable machine having a movable part. Morespecifically, user authentication may be performed on an informationterminal or the operation of an autonomous robot may be controlled,based on the information obtained from a detector according to at leastone of the above embodiments of the present disclosure. Alternatively,the results of detection that are obtained by a detector according to atleast one of the above embodiments of the present disclosure, which arethe information about the situation inside or outside a mobile objectsuch as a vehicle, may be used for a driver-assistance system.

The optical device according to the embodiments or their modificationsof the present disclosure may be used for a pump source or excitationlight source of solid-state laser, instead of the light source of adistance-measuring apparatus. Moreover, the optical device according tothe embodiments or their modifications of the present disclosure may beused as a light-source device such as a projector, in combination withan optical element that converts the wavelength of the light exitingfrom a surface-emitting laser module such as a fluorescent material.

Note that numerous additional modifications and variations are possiblein light of the above teachings. It is therefore to be understood thatwithin the scope of the appended claims, the disclosure of the presentdisclosure may be practiced otherwise than as specifically describedherein. For example, elements and/or features of different illustrativeembodiments may be combined with each other and/or substituted for eachother within the scope of this disclosure and appended claims.

What is claimed is:
 1. An optical device comprising: a first substratehaving a first plane and a plurality of elements, the plurality ofelements being disposed on the first substrate to emit or receive lightin a direction intersecting with the first plane; and a second substratehaving a second face that faces the first plane, the second substratebeing provided with a plurality of lenses disposed to correspond to theplurality of elements, the second substrate extending in a firstdirection parallel to the second face to contact the first plane, thesecond substrate having a joint used to determine spacing between thefirst substrate and the second substrate, the joint contacting the firstsubstrate with an area smaller than a maximum size of cross-sectionalarea parallel to the second face of the joint.
 2. The optical deviceaccording to claim 1, wherein the joint includes a first part contactingthe first substrate, and a second part apart from the first substrateand intersecting with a normal to the second face.
 3. The optical deviceaccording to claim 2, further comprising an adhesive disposed betweenthe first plane and the second part.
 4. The optical device according toclaim 1, wherein the joint continuously surrounds the plurality oflenses in a planar view of the second face.
 5. The optical deviceaccording to claim 4, wherein the joint has a rounder shape at an outeredge in the planar view than the second substrate.
 6. The optical deviceaccording to claim 1, wherein the joint contacts the first substratethrough at least some of an outer region of the second substrate.
 7. Theoptical device according to claim 1, wherein the joint is made of a samematerial as the second substrate.
 8. A light-source device comprising:an optical device including a first substrate having a first plane and aplurality of elements, the plurality of elements being disposed on thefirst substrate to emit or receive light in a direction intersectingwith the first plane, and a second substrate having a second face thatfaces the first plane, the second substrate being provided with aplurality of lenses disposed to correspond to the plurality of elements,the second substrate extending in a first direction parallel to thesecond face to contact the first plane, the second substrate having ajoint used to determine spacing between the first substrate and thesecond substrate, the joint contacting the first substrate with an areasmaller than a maximum size of cross-sectional area parallel to thesecond face of the joint; and a driver configured to drive the opticaldevice, wherein each one of the plurality of elements is an element toemit light.
 9. A detector comprising: the light-source device accordingto claim 8; and a detection system to which light emitted from thelight-source device and reflected by an object is incident.
 10. Anelectronic device comprising a controller configured to control theelectronic device based on information obtained from the detectoraccording to claim 9.